Checks if an association between two DAG nodes already exists, i.e.
does not need to be introduced when adjusting for a shared child etc.
Internally called by dag.adjustment.
assoc.exists(dag, a, b)A boolean indicating whether or not an association between first node and second node already exists.
The DAG to be dealt with.
First node.
Second node.
Lutz P Breitling <l.breitling@posteo.de>